


Tail as old as time

by QueenPotatos



Category: Free!
Genre: Fluff, M/M, abusive use of italics and this kind of - annoying - writers' habit, at inappropriate times, in rin's arms, silly fluff, the fic where Haru transforms into a mermaid...Randomly
Language: English
Status: Completed
Published: 2020-02-27
Updated: 2020-02-27
Packaged: 2021-02-28 05:20:51
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,628
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22928617
Author URL: https://archiveofourown.org/users/QueenPotatos/pseuds/QueenPotatos
Summary: Whatever this is, it can’t be a blessing.Haru’s legs merge into one single blue limb, his jean sacrificed in the process and the sharp scales are back again. Rin has the presence of mind to put his arm under Haru’s knees before he fully transforms and that’s pretty it.Haru is a mermaid.Rin is holding him bridal style, and they are stuck in a fitting room too small for them both with the rest of their errands scattered on the floor – including Steve’s diet cans..(A story Rin is unable to make heads or tails of!)
Relationships: Matsuoka Rin/Nanase Haruka
Comments: 12
Kudos: 76





	Tail as old as time

**Author's Note:**

  * For [ladyeos](https://archiveofourown.org/users/ladyeos/gifts).



> This is a gift for my waifu. Eos I love you. I'm so glad you enjoyed it and tolerate all my weird commas' placements. This is true love for sure.

* * *

The first time it happens Haru has at least the courtesy to fit in an appropriate environment – it is so odd  _ and yet _ not that much considering it’s  _ Haru,  _ of all the people, whom this little - how to say, misadventure? – occurs to.

Rin curses, internally; why did he choose to fetch him this morning when it’s usually Makoto’s job?

He disguises his surprise with an appropriate frown. “Haru. Tell me it’s just a costume. I promise I won’t judge you.”

And Haru – the  _ nerve _ – shakes his head, nonchalant and unaffected as ever. Worse, he shrugs, his eyes going from Rin’s unamused face to the shining blue mermaid tail that seems to have replaced his human legs.

Rin steps inside the bathroom but no, even closer it still looks like the real deal. He bites the inside of his cheek – carefully not to draw blood, in case Haru would be able to smell it with his new…situation? – then kneels, crossing his arms on the bathtub to be eye level with Haru.

His mind is blank for a moment, a time not filled with Haru’s words of explanation or a single coherent thought from them both; then Rin finally talks and it’s so fucked up he wonders where his thoughts have travelled.

“Can I touch it?”

Haru’s scales, it turns out, are as sharp as they are blue. It’s only after Rin gasps that Haru finally looks back at him and when their eyes meet, Rin has the ill feeling even Haru has no real idea of what’s happening to him, or why, for all that matters. But there he is, transformed into a mermaid in his bathtub on a Sunday afternoon just before their joint practice.

Rin studies his face for a moment, to see if anything else has changed – the curve of his nose, the shape of his eyes, his neck; everything still looks the same, it could be a really well made tail after all – but then-

“Rin.” Haru talks as if the air has been cut out of his throat, a dash of panic mixing with his usual composed self. “It’s going away.”

There’s no way to tell if Haru feels sad or happy or stunned by that – and obviously there’s a part of Rin that is sure he must be kind of frustrated by the whole…event – as for Rin, the only conclusion he allows himself to draw is that someone must have put something really strong in his energy drink to have such hallucinations. It only takes a minute but slowly the scales tear away from Haru’s tail and the blue of the skin underneath melts in the warm water of the bath, revealing Haru’s bare – human – legs, along with pieces of shredded tissue that are suspiciously black and violet, matching perfectly with what Rin remembers Haru’s swimsuit to be, meaning that 1. Haru was wearing it in his bathtub (again, nothing out of the ordinary) when he transformed, 2. Haru is therefore actually naked, and 3. Rin is still staring at his legs.

For some reason, Rin decides it’s too much information at once for his poor head and exits the bathroom without his usual grace – which means he tripped over his feet and almost hit his forehead on the door before opening it. Outside, Nagisa and Makoto are looking at him with eyes big as space saucers. He must look, puzzled? Traumatized? Oddly aroused?

_ Wait, what- _

“He wasn’t wearing his swimsuit.” Is all he managed, and he breathes fresh air again when Makoto’s face morphs from his ‘mom is worried do I need to call the cops’ into his ‘mom understanding magic flair’ self, there’s a uneasy smile on his lips when he speaks, “I know, it can be a little unsettling...” and Rin wants nothing but to figure out what he really meant by that.

(But of course, he does.)

Their joint practice is a pure disaster, one because Haru hardly swims or looks at the pool or at Rin, for what it’s worth, and so if Haru doesn’t swim, Rin doesn’t quite do so either – he’s in the pool, he moves his arms and legs in the proper form to advance in the water gracefully and faster than anyone else there but it’s  _ not _ swimming. Second, Rin is restlessly watching over Haru and his legs just in case something… happens, again, and he sees then how much Haru avoids him all together, rejects his attention entirely and doesn’t even start to acknowledge his presence or attention.

There’s no need to lie to himself about it – Rin is awfully bad at that anyway. It hurts. A lot more than the thin scar he got on his fingertips, a reminiscence of Haru’s tail on his skin, a clue – a proof – that this hadn’t been his imagination, or that, perhaps, if it was a dream he hadn’t awakened yet.

Haru’s vulnerable gaze flashes in his mind each time he runs his thumb on the wound, and the more he thinks about it the more he feels there was something more underneath, something he couldn’t grasp because Haru deliberately put it out of reach.

* * *

The second time.

“You’re kidding me right?”

But judging by the panic in his eyes, Haru is not.

“Hold me!”

They are – well,  _ were _ – standing in the middle of the mall, running some errands for various people – Gou, Nagisa, the twins,  _ Steve _ – when Haru throws himself at Rin’s neck. He hurries to the closest clothes store and drags Rin into the first fitting room – Rin curses because it’s a women store for fuck sake! – and helplessly watches the transformation under his very eyes. Whatever it is it can’t be a blessing. Haru’s legs merge into one single blue limb, his jean sacrificed in the process and the sharp scales are back again. Rin has the presence of mind to put his arm under Haru’s knees before he fully transforms and that’s pretty it.

Haru is a mermaid. Rin is holding him bridal style, and they are stuck in a fitting room too small for them both with the rest of their errands scattered on the floor – including Steve’s diet cans.

After a while, Rin sighs.

“I’m sorry.” Haru says flatly. His voice is hollow, as if he wasn’t really here, “I don’t know why it’s happening.”

“That’s the last thing I’d like to hear.” His bangs are tickling the birth of his nose and with his hands full, Rin can’t scratch and it’s going to drive him crazy – that, more than the whole situation,  _ obviously _ . Haru is visibly (and understandably) tense in his arms and acts the same as few days prior, meaning he is looking at the floor – if Rin had to guess, he’d say at one of Steve’s cans – as if he could disappear out of the crime scene if he wished for it hard enough.

“When did it…I mean, how…”

“I don’t know, Rin.”

“How could you be so nonchalant about it ?!”

He can see it happening before his eyes, before it actually does. Haru raises his head, their eyes meet and he shrugs the problem away. “It would still be there whether I panic or not.”

“So you just, chose not to. Like. There’s a tail that tears all your clothes randomly and you just... stay composed.” Rin shakes his head to move his bangs from his face. “I don’t get it.”

“Me neither. Do you need help with your hair?”

Another – successful – tentative bid to change the subject when Haru’s tail weights maybe 50 kilograms in Rin’s arms. Before Rin can answer though Haru takes the initiative, and his fingers brush just past his cheekbones to catch the rebellious bangs and up to his ear. The bangs immediately fall back in front of Rin’s face, who has somehow turned into stone at the tender and – sadly – unexpected gesture. He isn’t even sure he knows how to breath until Haru blinks a couple of time just a few centimetres from his face.

“Rin? Are you alright?”

He can feel his breath on his face. He’s this close to unceremoniously dropping Haru on the floor. 

And then, Haru stares at him and the weird look is back for only a moment – Rin blinks himself and it’s gone – but he’s certain of what he’s seen, there’s no way he had imagined it this time there is something inside Haru’s eyes that shines-

Haru sighs and rests his head on his shoulder, and for some obscure reason Rin’s mind short-circuits.

They aren’t used to such proximity. The closest they have been, last year, was after the relay, after Rin was saved and had had the need, the irrepressible necessity to have Haru close to his chest and heart in the heat of the moment. Now there is no adrenaline, there’s rather a calmness in the absurdity of the situation – Rin has to remind himself when his arms feel numb that Haru has a  _ mermaid tail _ – and it’s with a certain delicacy that Haru just poses his head, just so lightly on his shoulder, almost as if he was fragile, made of porcelain – or perhaps it’s him who Haru doesn’t want to hurt.

It’s true that Rin holds his feelings close to his heart and, concerning a certain Haruka Nanase they tend to overflow without his consent and spread endlessly to whoever had the misfortune just to mention the name in front of him - especially if they’re separated by an Ocean or talking about anything close to swimming and relays. He often doesn’t realize how painfully obvious he can be when Haru’s not here to hear, but some heavy glances from Sousuke and his sister taught him the immensity of his crush and the  _ also _ immensity of the second hand embarrassment both of them get from watching. Having Haru this close reminds him of them, the feelings that he is not that good at hiding, and makes him wonder how on earth Haru hasn’t noticed yet.

The only good thing about the ‘tail gate’ so far is that, if Haru remains calm when he’s literally not a human being anymore, there’s no way he would freak out when suffering from Rin’s obvious crush. So maybe he knows. Maybe he doesn’t because it’s Haru after all, but maybe he does, and - is that supposed to ease his heart or make it beat twice as fast?

The latter.

“Rin!”

There’s something tickling on his cheek – Haru’s fingers, he figures – and down his chin, Haru forces their eyes to meet. “I’m morphing again.”

The scales drop on the floor one by one, leaving Haru half-naked in Rin’s arms and it’s with a vibrant blush on his cheeks that Rin finally gets what Makoto meant by  _ that _ .

Haru’s cheeks coloured just as crimson as he puts his foot on the floor and gasps, having stepped on one of his scales and hurt his foot.

“I’m not carrying you back to your house like this.”

By ‘like this’ he meant bridal style, but a more pressing matter arouses: Haru is half naked. If he had had the presence of mind to take off his shoes as soon as he felt the transformation the same cannot be said for the rest of his underclothes. He looks back at Rin, really slowly, his cheeks somehow redder than before. He doesn’t have to speak, Rin gets what he wants anyway.

He peeks his head with caution before he exits the fitting room, alone. He can feel his cheeks still burning and just knowing he had blushed so much in front of Haru maintains the heat as vibrant as it can, meaning he doesn’t know if the sales assistant stares because he’s 1. red, totally 2. going out of a fitting room in a women’s dress shop, 3. totally her style. Maybe it’s a mix of the three. He takes the first panty he can get his hands on and skinny jeans and comes back.

“That’s not my size!” Haru hushes, visibly annoyed.

“How would I know?!” He not so much hushes, exasperation storming, which ends up provoking everything they have tried to prevent.

“Can I help you?”

Rin is still red, and by the time he makes it to the cashier and back to the fitting room for Haru to leave decently, he has lost his dignity at least ten times.

* * *

They don’t speak for days, days turn into weeks. Rin kept the scale he had to get from the floor into his shopping bag – and he remembers, them, on all fours, picking tiny scales one by one carefully not to hurt themselves, and feels mortified. Before their next joint practice he risks a text, inoffensive.

_ ‘You okay?’ _

He blinks.

_ ‘Yeah.’ _

The reply comes rather quickly for Haru standards.

He types, then erases, then types again.

_ ‘Did you transform again?’ _

Writing doesn’t make justice to the indecision of his heart. He sees Haru struggle just as much, he can see the icon on his phone typing, stopping, typing again.

_ ‘A couple of times.’ _

Rin’s chest burns to the bottom of his throat.

_ ‘Have you talked to someone about it? Makoto? A doctor?’ _

_ ‘No.’ _

Typical.

_ ‘And you?’ _ Haru sends before Rin can type again.

_ ‘No. _ ’ Is Rin’s answer, even if he only did so because he was sure Haru couldn’t have kept this kind of secret to himself for so long.

Rin lies down on his back and stares at the ceiling, his phone on one hand, a couple of scales on the other. Sousuke arrives at this moment and halts at the sight.

“What’s going on?”

Rin hides the scales under his blanket. “Nothing.” He lies, unnecessary since Sousuke always knows when he does, and knows when there’s something up with Haru, usually before Rin does. But he has the delicacy not to point it out, and they go out for dinner as they usually do with the rest of the team.

* * *

The third time, it’s before Rin goes back to Australia.

And it is nothing like the other times – it’s not unexpected, it’s not embarrassing, it just feels right in all the odd possible ways, it feels like  _ them _ .

Days prior they have talked, alone.

“I have it under control.”

“But it doesn’t mean you should keep quiet about it,” Rin tries – manages, he doesn’t even know how – to remain calm and quiet as he whispers; they’re walking a bit behind the others and none of them seem to mind for a pretty varied amount of reasons, all wrong of course because how could they know  _ Haru randomly transforms into a mermaid but he has it under control- _

“I mean, this is a serious issue. How about your health? What if it’s something serious? What if…what if it becomes per…permanent?” He struggles with the words as much as he doesn’t want it to happen. A world without Haru – well, without Haru standing on legs – wouldn’t feel the same, wouldn’t be half as worth as it should be.

Rin is cool with the knowledge now. It’s too tiresome to fight with himself, he has other battles to win.

“It won’t be. I just…” Haru pauses, sends him a look –  _ the _ look – and Rin can tell he’s not going to like what comes next. “You’re not going to like it but-“

He rolls his eyes.

“I can feel it. I can…guess, why it happens. I’ve been able to control myself lately that must mean I’m right.”

It’s true that, during their trip in Australia Haru didn’t-

Rin stops the memories from entering his thoughts before his cheeks start to burn, only to find out he’s too late. Especially the part where they slept together – he’s pretty sure he’s crimson right now, judging by the way Haru stares at him, visibly worried.

“And, did you find out other…abilities? Cool stuff.” He says to distract Haru from his burning face. “Like can you breathe underwater and smell blood?”

Haru looks away, unamused, “No.” He pouts. He’s adorable, Rin can’t help but laugh a little and it’s a different kind of warmth he feels when he does, that had nothing to do with embarrassment.

Rin had asked, relentlessly, how Haru got stuck with this…curse? – that wasn’t Haru’s way to put it of course, he considers his misadventure a ‘real blessing’ – and all of his attempts were crushed against Haru’s ever going and firm ‘No.’ He hadn’t wished upon a star, hadn’t made a pact with Satan or another deity, hadn’t saved a mermaid when he was little, his mother had always had two legs and no tail, his grandmother wasn’t a witch, and so on…

“Mackerel,” is Haru’s best guess, which tells a lot about how hard he had thought the problem – which isn’t really one for him in a sense – through. “It must be mackerel.”

“Great. I can see the headlines. A boy eats so much fish he turns into one.” Rin says flatly just to tease, which works like wonders – now Haru is mumbling something he cannot quite get, something like ‘I’m not eating that much fish’. But when Rin smiles fondly his frown disappears. “I was joking.”

Haru blushes, a sight so rare Rin isn’t sure it’s real, before turning his gaze away.

He asks him to meet him at the pool at night. 

The third time happens during a race.

Rin is about to pass him when it happens, he feels it in the water before he can see, and he’s not surprised when Haru reaches the finish line first. Rin is breathless when he emerges but not from exhaustion; he feels small and blessed and there’s a kind of unique joy dancing in his chest, as if he had been given the rare chance to see a miracle occur just for himself.

Haru, his arms crossed on the float line, is smiling like he has rarely done so before.

“So?”

Rin is still speechless.

“As it turns out, I can’t breathe under water.” He says, and the smile vanishes to Rin’s despair.

“But you already knew that.”

Haru shrugs, “I know, but, somehow,” there’s a pause, Haru takes a breath, “Somehow I thought I could, with you.”

Rin tilts his head, not sure to follow where Haru’s thoughts were going – afraid to?

“I had a…hunch?” Haru turns his head so his cheek rests on his arms and looks away, far away from Rin, a vain attempt to hide his blush, certainly. “My intuitions were often right with…this so, I thought…but, not this time.”

“What were your other hunches? What were you right for then?”

It’s the very first time he sees Haru transform willingly, meaning that yes, Haru must have found some of the answers he’d been desperate for a while. As impossible as it looks, Haru blushes even harder before disappearing under water but not without murmuring a cute ‘nothing’, which makes Rin’s heart skip a beat.

They swim until it’s dark enough to see the stars. Rin is leaving in a few days.

“This. It’s just for you.”

Rin looks at the sky; he thinks Haru refers to the view – and it’s incredibly romantic, especially for Haru’s standard and so it doesn’t feel  _ quite right _ – but Haru is not looking at the stars, he’s looking at him.

“You’re the only one. Who saw me like this. It is just for you to see.”

And it doesn’t sound like it’s what Haru wanted all along but more like a crude fact, something Haru had no power on. It’s only when he’s here.  _ You’re the only one _ -

Haru rests his head on his shoulder. Rin goes still. Too much information at once, too much romantism for a night, too much  _ Haru. _

“What? You spend your days using my shoulder as your armrest and I shouldn’t use yours as a pillow for once?” 

Haru can be a pest when he wants, but it’s something Rin can work with. He relaxes, lets out a sigh he’s been holding for a while. “You’re impossible.”

They remain silent, enjoying their proximity until it was clearly too cold to stay in the water. All along Haru had kept his mermaid form, and when asked if he wasn’t afraid to transform randomly, he had replied by shaking his head, and said, “I don’t want to, not yet.”

When he hears Rin’s teeth chatter though, Haru turns his head. “Rin.” He calls. His hand curls under his chin.

Look at me his eyes say, something Rin happily obliges. And just like that he feels it’s happening before the first scales reach the surface. He feels it when Haru’s foot settles just next to his, feels the uncertainty in his gaze before he takes another step forward and Rin lets him, feels like he’s been struck by lightning when finally Haru holds him in his arms.

“I know you have to, but, it’s going to be lonely without you.”

Rin wants to cry. Really, he would like nothing but to cry but there’s this constant reminder that Haru is naked and hugging him and Haru is naked he’s totally naked  _ naked naked- _

“You won’t have time to miss me. If you don’t practice enough I’ll come back to beat your mermaid ass.” He grins, but there’s something running from the corner of his eyes to his lips and he tastes salt, and he knows. “Don’t slack off.”

Haru returns his daring smile. “I won’t. By the way I brought another swimsuit, could you-“

“Oh actually I brought a spare too! Figured something like this would happen…”

Rin is out of the pool in a second; Haru watches his back fondly and sighs once he’s safe from anyone’s gaze. The secret of his heart would remain concealed for now, but it’s alright. Only Rin holds the keys, and it’s alright.

* * *

“The water favours you.” Albert tells him a couple of months later. If only he had any idea of what he’s talking about...

* * *

A couple of months later  _ – Epilogue. _

Rin turns on his phone as soon as he lands, before he’s out of the plane. He’s got a message already, ‘I’m here’ with a small picture of Haru drinking something on a cup, he cannot guess what exactly from this angle. Haru is pouting, but his eyes are bright; he’s happy to be here and so Rin smiles – dumbly, alone, at his phone; he’s got enough self-esteem to ignore the looks the passenger next to him is sending him.

He almost catches himself running with his suitcase when he sees Haru’s there – which means he realizes he  _ was runing _ when he’s this close to jump at his neck and hold him, and he curses,  _ shit, not again _ ; he thinks of Natsuya and all the things he told him about Haru and him without realizing, and he is really stupid, so stupid…

Long story short, he’s blushing but fuck, why not after all?

“Rin.”

Their eyes lock and Haru smiles, and that's all it takes. Years of longing, years of self-control and all it takes is a little smile and Haru saying his name. Why can’t things happen like in a Hollywood romance movie?

He’s going to do it, right now, in front of the whole airport.

Rin holds Haru who gasps when their chests meet, as expected, it is perhaps not how he had imagined their reunion to be. Air leaves their lungs. Rin can’t look elsewhere but at Haru, the shape of his lips, rosy and thin and  _ desirable _ , the course of his neck going down to his collarbone, barely visible before they disappear under his shirt, and his  _ eyes _ \- oh no his eyes – he knows that look – he would recognize it  _ anywhere- _

“No. Haru. Please, not here.” Not  _ now _ for fuck sake.  _ “Don’t you dare.” _

Panic. Haru is panicking because he is transforming again.

“I’m sorry.” Is all he can say as he scans the place for a clever retreat strategy. “I am so sorry I can’t help it.”

“You told me you had figured it out!” Rin hisses and he doesn’t really know why he’s so mad at him because he knows it’s not – really – Haru’s fault but he was this close to kissing him and he fears, more than anything right now, that he – that they – have missed their chance and-

The noise of Haru’s jeans starting to be ripped off by the transformation brings him back on solid ground. Back-up plan, right now.

Rin runs with one hand supporting Haru and the other dragging his suitcase to the nearest toilets. He locks themselves in the first cubicle that is empty and if it’s more spacious than the changing room they once shared in a similar situation, the 23 kilograms suitcase sure reduces their vital space.

He holds him bridal style again and soon feels the scales hurting his palm, thinking about which ones of his pants he’ll have to lend him before they can decently get out of this hell.

“For fuck sake, Haru.” He can’t help it, he’s happy but annoyed, he’s got Haru back in his arms after months of missed calls and opportunities and things are back where they left them, but damn, why,  _ now- _

“…Welcome back?” Haru tries, with a smile that is shy, and he moves his fins as if it was waving at him and it’s the cutest thing Rin had had the chance to witness in his whole life.

He sighs. Why did it have to be him?

“I’m home, I guess?” He looks back at Haru’s tail. “This is far from an unfamiliar sight after all.”

Haru’s smile deepens, he rests his head on his shoulder like he so usually does. This really could feel like home.

Rin can feel the  _ moment _ is coming back. They’re staring at each other, and even manage to omit the noise of other human beings using the toilets for what they were built for in first place – not the most romantic settings Rin concedes, but still, he’ll have to make do with what’s he’s got – when the first scales fall off, breaking the beauty of the moment before Rin can risk to capture Haru’s lips. 

Haru looks at the suitcase, “I’ll, um, have to borrow some of your stuff.”

“Really? Thought you were going to get out of here naked.”

“Rin!” Oh he adores it, the slight blush on those cheeks, his pupils going dark and wild, his voice, unsettled. “I…can’t!”

“Relax! I was joking!” All the scales had dropped on the floor by now, Haru has his legs back. “Okay, let’s pick it up and get you some clothes.”

Once they are finally finished – well, presentable – Rin opens the door with a huge smile on his face.

Only to be stared at by a stranger holding a couple of Haru’s scales that had escaped under the door.

Haru freezes while Rin studies the guy, who is perhaps the more stunned of the three. But by sheer luck, the guy is a westerner.

“Don’t worry, judging by his looks,” Rin briefly looks down at his socks and sandals fashion before it burns his retina, “He’s German. Probably doesn’t understand a word we say.”

Which turns out to be quite right but also quite practical. Rin explains a few lies in English while Haru escapes. 

“Seriously, Haru, we really need to find a way to cure your spontaneous merman transformation, because it’s getting ridiculous and happening at the most, inappropriate, times.” He says once they’re out in fresh air.

“It’s not a curse!” Haru hisses, dragging Rin’s suitcase – perhaps as a way to apologize? _“It’s a blessing!”_

Rin raises his eyes to the heavens. 

He hopes it’s not mackerel because they will never get away from it.

  
  
  
  


**Author's Note:**

> Knaps you're next.
> 
> I used all my fluff energy for the entire year with this, so expect nothing but sadness and death for the next ones XD #teamangst will come back...soon...


End file.
